大断面隧道锚杆设置的优化分析

Optimum Analysis of Large-Section Tunnel's Bolts Location by FLAC

目前数值模拟己经成为地下工程分析中十分有效的方法。对于大断面公路隧道,可以采用数值模拟方法对隧道支护体系进行分析,从而达到优化设计的目的。采用有限差分程序FLAC分析软岩大断面隧道在同类围岩条件下用同一种方式开挖时,分别采取不同的锚杆布置方式时围岩应力分布、锚杆受力状态对围岩稳定的影响等,可以确定出软岩大断面隧道在一定的围岩级别下最优的布锚方案,并可为大断面隧道与地下工程的锚杆支护参数的优选、技术规范的修订提供参考。

Numerical simulation is a very effective analyzing method in underground engineering. For large-section highway tunnel, numerical simulation can be used to analyze the support system of the tunnel to achieve optimum design. The finite difference software （FLAC） has been employed in this paper to estimate the influences of various bolts layout on the distribution of stress of surrounding rock, stress of belts and stability of surrounding rock. These analyses are based on the assumption that the surrounding rock and the excavation method are the same. Consequently, the optimum bolts layout scheme of large-section tunnel in weak rock can be obtained at certain class of surrounding rock from the foregoing calculation results. It can provide reference for the optimization of design parameters of bolts in large section tunnels and underground structures, and also for the amendment of technical specifications for design and construction of tunnel.